Thursday, September 30, 2010

In a Scientific American essay based on their new book A Grand Design, Stephen Hawking and Leonard Mlodinow are now claiming physicists may never find a theory of everything. Instead, they propose a "family of interconnected theories" might emerge, with each describing a certain reality under specific conditions.Most of the history of physics has been dominated by a realist approach. Scientists simply accepted that their observations could give direct information about an objective reality. In classical physics, such a view was easily defensible, but the emergence of quantum mechanics has shaken even the staunchest realist.

In a quantum world, particles don't have definite locations or even definite velocities until they've been observed. This is a far cry from Newton's world, and Hawking/Mlodinow argue that - in light of quantum mechanics - it doesn't matter what is actually real and what isn't, all that matters is what we experience as reality.

As an example, they talk about Neo from The Matrix. Even though Neo's world was virtual, as long as he didn't know it there was no reason for him to challenge the physical laws of that world. Similarly, they use the example of a goldfish in a curved bowl. The fish would experience a curvature of light as its reality and while it wouldn't be accurate to someone outside the bowl, to the fish it would be.

"In our view, there is no picture or theory-independent concept of reality. Instead we adopt a view that we call model - dependent realism: the idea that a physical theory or world is a model (generally of a mathematical nature) and a set of rules that connect the elements of the model to observations. According to model - dependent realism, it is pointless to ask whether a model is real, only whether it agrees with observation. If two models agree with observation, neither model can be considered more real than the other. A person can use whichever model is more convenient in the situation under consideration."

This view is a staunch reversal for Hawking, who 30 years ago argued that not only would physicists find a theory of everything, but that it would happen by the year 2000. In his first speech as Lucasian Chair at Cambridge titled "Is the end in sight for theoretical physics?," Hawking argued that the unification of quantum mechanics and general relativity into one theory was inevitable and that the coming age of computers would render physicists obsolete, if not physics itself.

Of course, Hawking has become rather well known for jumping way out on a limb with his public remarks and for decades he embraced supergravity as having the potential to solve theoretical physicist's ills, even hosting a major conference on it in 1982. However, but Hawking has never harbored allegiances to theories that describe a physical reality.

So, while two well-known physicists coming out against a theory of everything is compelling, it really shouldn't seem like anything new for Hawking.

"I take the positivist view point that a physical theory is just a mathematical model and that it is meaningless to ask whether it corresponds to reality. All that one can ask is that its predictions should be in agreement with observation."

Wednesday, September 29, 2010

It's 2 a.m., and the noise from your upstairs neighbor is keeping you awake again. Take solace in the fact that by living above you he may be shortening his life, even if only by a tiny fraction of a second.

Nearly a century ago, Albert Einstein suggested that time should move faster the farther away you are from the surface of the Earth. Now scientists have tested this theory at the small distances we travel up and down every day. Using the world's most precise clocks, they confirmed that our wristwatches tick at a slightly different speed when we ride an elevator, climb a flight of stairs, or even sit upright in bed.According to Einstein's theory of general relativity, big objects with lots of gravity -- planets or stars -- bend the fabric of time and space, like bowling balls on a trampoline. The closer you get to these objects, the stronger the pull of gravity and the slower time moves. An astronaut watching a clock fall into a black hole, for example, would see its hands gradually slow down as the pull of gravity increases. The second hand would move tick once every hour, then once every decade, and finally appear to stop altogether.

For half a century, scientists have experimented with ways to spot this effect on Earth. In 1976, the Smithsonian Astrophysical Observatory launched a rocket that carried a clock 6,000 miles away from the ground, where the pull of gravity is weaker. When the clock returned to the surface, it had sped up -- compared to clocks on the ground -- by about one second every 70 years. Time dilation over great distances has also been measured in clocks flown around the world on airplanes and sent to Mars on spacecraft, and satellites in orbit must compensate for it to keep GPS networks functioning properly.

But spotting the subtle changes in time that happen over the smaller vertical distances we move in our daily lives -- a matter of feet and inches -- is much more difficult. It requires an exceptional clock billions and billions of time better a wristwatch.

Time Is Relative

Chen-Wen Chou is a researcher at the National Institute of Technology in Boulder, Colo. and a member of a team that recently developed just such a device -- the world's most precise clock.

This optical atomic clock uses lasers tuned to the vibrations of a single atom of aluminum, which wobbles more than a quadrillion times per second (a quadrillion is a 1 followed by 15 zeros). It keeps time to within a second for 3.7 billion years.

Searching for time dilation, Chou and his colleagues put the clock on a table and raised the table by a foot. After a long observation, they found that the time on the raised clock was slightly ahead of the time on a second clock kept below.

"The difference at a foot of height over 100 years would be about 100 nanoseconds, said Chou. "That's about a hundred billionths of a second."

Time, then, does not flow at a constant rate in our daily lives.

"These small differences would have been undetectable for the previous generation of atomic clocks," said Chou, who published the results in the journal Science.

All other things being equal, living upstairs causes you to age slightly faster than living downstairs. And even with both feet planted firmly on the ground, parts of your body at different heights will age differently.

"The biochemical processes in our body are governed by the same physical laws as clocks," said Clifford Will of Washington University in St. Louis, Mo., who was not involved in the research. "Those in the tops of our heads will run slightly faster than those in the soles of our feet."

Even at the tops of skyscrapers, though, this difference is far too small to be noticeable.

"The world's tallest building is about 850 meters (half a mile) tall," said Alan Kostelecky, who studies relativity at Indiana University in Bloomington. "If you lived there for a million years, the difference would be a few seconds."

Running With Relativity

Gravity isn't the only thing that can warp time. According to another one of Einstein's theories, special relativity, time slows down for an object when it moves. A twin launched into space on a ship traveling near the speed of light would find on his return that he had aged more slowly than his brother left at the surface.

To measure this effect, Chou moved one of his clocks slowly -- at speeds similar to walking or running -- and compared it to a stationary clock.

He confirmed that when we walk up a flight of stairs, time is at war with itself. Being farther from the pull of Earth's gravity causes our clock to tick faster, but moving counteracts this effect.

If you live in a second-story apartment, and the thought of the universe stealing a split second of your life keeps you awake at night, science offers a solution. Just run in circles to keep your watch in synch with clocks on ground floor.

Tuesday, September 28, 2010

In today's podcast, PhysicsBuzz talks to Marc Kuchner from NASA Goddard about planets orbiting around binary stars. Kuchner and his colleagues recently reported their findings from the Spitzer Space Telescope, which showed that planets around binary stars can have a rough life. They discovered a ring of diffuse dust and believe it may be all that's left of an unfortunate planet that was too close to its dying star.

"These kinds of systems paint a picture of the late stages in the lives of planetary systems," Kuchner said in a NASA press release last month. "And it's a future that's messy and violent."

Monday, September 27, 2010

In recent years, the ability to create laboratory analogs has become a popular way to examine theory that can't be directly observed in nature.

Last week, I blogged about how the properties of a vacuum might play a dramatic role in the evolution of relativistic stars, in the blog I talked about how the study authors said we wouldn't be able to directly detect Hawking Radiation in the universe. Now, it seems some clever physicists from the University of Milan have found a way to detect Hawking Radiation after all: sort of. The physicists say they've observed the radiation in a clever lab analogy with a so-called white hole, which is often thought of as the inverse of the black hole.Normally, when an antiparticle-particle pair form they release their energy immediately and mutually annihilate. Hawking radiation proposes that when the pair starts to cross over the event horizon of a black hole, one photon can be sucked in while the other is released. Because the free photon can't return to the vacuum from which it came, it "becomes real" and gains energy at the expense of the black hole. This process causes the black hole to gradually lose mass.

It's clear why such an effect would be difficult to observe in the cosmos, but a white hole can also create an event horizon and provide an earthly test. Instead of sucking light inside it like a black hole, a white hole causes light waves to come to a complete stop. In the research, which is set to be published in the journal Physical Review Letters, the Milan physicists were able to create a white hole by firing ultrashort infrared laser pulses through fused silica glass.

They say the measurements they made of their gravitational analog confirm what physicists have long predicted would happen in theory and "demonstrates a spontaneous emission of photons." They also claim they were able to distinguish the effect from other causes for photon emissions.

If confirmed, such a finding would demonstrate that Hawking radiation should indeed have a major impact on the endstate of our universe.

Friday, September 24, 2010

Update: check out our podcast, which features another conversation with Marc Kuchner about his research on colliding planets and the prospects for life in binary star systems.

With help from a supercomputer capable of 67 trillion calculations per second, astronomers at NASA Goddard have determined what our solar system would look like to an alien astronomer. The simulations track the interactions of 75,000 dust grains in the Kuiper Belt, which is an icy region out beyond Neptune where millions of small bodies (including Pluto) orbit the sun.

"The planets may be too dim to detect directly, but aliens studying the solar system could easily determine the presence of Neptune -- its gravity carves a little gap in the dust," Goddard astrophysicist Marc Kuchner said in a press release yesterday. "We're hoping our models will help us spot Neptune-sized worlds around other stars."The images were created from simulations on NASA's Discover supercomputer and are like an infrared snapshot of what the Kuiper Belt would look like from a distant world. What's even more striking is that the images look alarmingly like this Hubble image taken a few years ago of the star Fomalhaut, which shows a planet orbiting inside of what now appears to be a region very similar to our own Kuiper Belt.

Modeling tens of thousands of dust grains in the system was no easy task, and some questioned whether it could be done at all. The astronomers had to account for interactions not just amongst the dust, but also with the outer planets, sunlight and the solar wind.

"The size of the model dust ranged from about the width of a needle's eye (0.05 inch or 1.2 millimeters) to more than a thousand times smaller, similar in size to the particles in smoke. During the simulation, the grains were placed into one of three types of orbits found in today's Kuiper Belt at a rate based on current ideas of how quickly dust is produced…

Using separate models that employed progressively higher collision rates, the team produced images roughly corresponding to dust generation that was 10, 100 and 1,000 times more intense than in the original model. The scientists estimate the increased dust reflects conditions when the Kuiper Belt was, respectively, 700 million, 100 million and 15 million years old."

"One of our next steps will be to simulate the debris disks around Fomalhaut and other stars to see what the dust distribution tells us about the presence of planets," said Christopher Stark, a co-author on the paper.

They've even been nice enough to encapsulate it in an easy to digest form.

Thursday, September 23, 2010

Everything we see in the world around us, scientists tell us, is made of atoms and combinations of atoms called molecules. Atoms are themselves made of tiny particles -- electrons, protons, and neutrons. Protons, in turn, are believed to be made of still tinier things called quarks. Is that the end of it? Probably not.Many physicists now believe that at a still lower level, matter consists of a network of vibrating strings. For several thousand researchers worldwide, using strings to explain complex phenomena is practically a crusade. The book "String Theory for Dummies" by Andrew Zimmerman Jones tries to capture the excitement of these developments without using any equations.

The reason strings are such a hot topic nowadays, Jones explains, is that the new theory not only helps to solve some long-standing problems in physics, but it also attempts to explain other, not-yet-observed phenomena such as time travel and the possible existence of extra dimensions.

One of the great virtues of string theory is that it tries to be a theory of everything. No, this doesn't mean explaining the meaning of life. For a physicist a "theory of everything" refers to an over-arching framework that explains the four known physical forces: the electromagnetic force, which holds atoms together and is also responsible for things like electricity, magnetism, and light; gravity, which holds stars together and keeps the planets orbiting our sun; the strong nuclear force which holds nuclei together; and the weak nuclear force, which is responsible for tearing nuclei apart through things like radioactivity.

In practice, contriving a theory of everything means reconciling the two great physics theories of the previous century: quantum mechanics and general relativity. Quantum science generally deals with matter at small scales (all those nested layers of particles), while general relativity generally deals with massive things like planets and galaxies. For the past century physicists have failed to bring these two mighty theories together.

String theory, at least on paper, seems to have succeeded. Gravity not only fits in with quantum behavior -- it is actually required by string theory. But here's the problem: string theory is exciting and elegant, but it’s still just a bunch of equations on paper. So far it has failed to offer any testable predictions.

Lee Smolin, who works at the Perimeter Institute of Theoretical Physics in Waterloo, Ontario, is one of the chief string skeptics. His book, "The Trouble With Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next," provides an interesting history of physics theories of the past two centuries. Smolin says that string theory has been around for 35 years. No previous major physics theory in past centuries has needed more than about ten years to be proved. So what’s taking so long?

To underscore the grave lack of experimental support for string theory, Smolin quoted physicist Richard Feynman's dislike of early forms of the theory: "'I don't like that they're not calculating anything,' said Feynman about string theorists. 'I don't like that they don't check their ideas. I don't like that for anything that disagrees with an experiment, they cook up an explanation.'"

Give us a chance, says Edward Witten of the Institute for Advanced Study in Princeton, N.J. Witten, not a founder of string theory but perhaps its most prominent practitioner and defender, argues that the complexity of mathematics used by the theory and the ambitiousness of the task of unifying all the known physical forces into a single framework must necessarily take time.

"String theory has been discovered in bits and pieces -- over a period that has stretched for nearly four decades -- without anyone really understanding what is behind it. As a result, every bit that is unearthed comes as a surprise," Witten wrote in an essay in Nature magazine. "We still don't know where all these ideas are coming from -- or heading to."

Some of the more forefront areas of particle physics are discussed in a clear way, things such as black holes, multiverses, and Higgs bosons. The book is well furnished with vivid illustrations. And as with so many of the other "For Dummies" books, there are plenty of text sidebars to handle sub-topics and other warnings and detour instructions that help the reader maneuver around this vast topic as if she were driving through Manhattan at rush hour. This journey through modern physics at rush hour is so filled with things to learn about that there isn't much room left for biography. Many personalities working in string theory today are mentioned but few are allowed the space to settle into our imagination.

Jones's book faces the issue of string theory's lack of experimental proof head on. He admits that there isn’t much evidence, but generally he takes Witten's view that we need still more time to settle the issue of string theory's validity and usefulness.

Jones runs the physics page on the popular About.com website, so he is used to grappling with down-to-earth explanations of tough subjects.

But does his book make string theory clear? Well, if you're a physicist the book does a nice job of summarizing string theory and its contributions to related subjects like mathematics and cosmology.

What about readers who are non-scientists but interested in learning about abstruse subjects like strings and are willing to do preparatory homework? Here again, Jones's book is worthwhile. It offers a nice exposition of classical theories of force (which explain why a ladder doesn't slide off the wall), quantum mechanics (which shows how atomic and sub-atomic objects get fuzzier the closer we look at them), and general relativity (which explains how massive objects warp the space in their vicinity).

And dummies? Will they like the book? Let's suppose that anyone who buys this book is not a dummy. But for readers who don't know much about science and who might have received something less than a top grade in high school geometry, "String Theory for Dummies" will be too great a challenge. String theory is a mountain of a subject with lots of foothills that need to be climbed before reaching the summit. These foothills, corresponding to all those careful explanations of particles, waves, forces, quanta, uncertainties, and extra dimensions only get us to about 1970. Then the really difficult climbing begins.

Unfortunately, that's the way it is with most of cutting edge science. It's hard to scientists themselves to understand, much less the rest of us.

Wednesday, September 22, 2010

There are moments in everyone’s life where a decision is made that affects everything that comes after it. Making a different choice long ago may have changed your life as well as your personality forever.

This is one of the themes that will play out for each character in season three of Fox’s hit television show "Fringe." At the end of the last season, two parallel universes collided. In season three, the cast will be using science fact and fiction to untangle them."Well, one area where we are letting the cat out of the bag is that season three will be very different than the first two," said Robert Chiappetta, one of the story editors for "Fringe." "In season one, science was neutral. Some of the characters used it for good and some for evil, viewers saw both sides. In season three, we are going deeper to understand why things have turned out the way they did."

Connecting physics to psychology, this season plays with the fringe science of parallel universes, where there are other universes related to ours that may have come from ours, but have different outcomes; chaos theory, where a small change in the beginning can cause a large impact at the end; and the psychological theory of nature versus nurture where your personality is shaped at birth, from your experience or a little of both.

"There are very crucial differences that trace back to key choices the characters have made," said Glen Whitman, another story editor for "Fringe." "What I love about this is that it connects chaos theory and how a very small difference in the initial conditions can lead to dramatic outcomes; it really gets to the idea of how decisions affect our lives."

"In life, you have to make a decision, you hope that it’s right and moral, but that doesn’t mean that it won’t impact other relationships," said Chiappetta. "This season is all about the fallout and consequences of the choices the characters make."

The results of biochemist Walter Bishop’s (played by John Noble) earlier life-and-death decision will continue to have a ripple effect throughout the season.

"Both Walter and Walternet (Walter in the other universe) started out the same, but they each made a different decision; now Walter is driven by guilt and Walternet by anger," said Whitman. "Viewers will constantly be surprised by the by the ways the characters in the two universes are the same and different."

Seeing the same character in two different worlds also gives viewers a chance to get to know the characters of "Fringe" in whole new light.

"You’ll see more of other character’s stories such as Astrid Farnsworth (played by Jasika Nicole), Nina Sharp (played by Blair Brown) and Agent Phillip Broyles (played by Lance Reddick)," said Whitman. "You’ll find out how they developed in the other universe. In this universe, Agent Broyles is divorced but in the other universe, he is more of a family man. Viewers will find out how the characters were exposed to different circumstances and how it changes them."

Some of the characters are more similar between the two worlds than others.

"Astrid’s character is the one that is the most different from this universe to the other, both personally and emotionally," said Whitman. "In the other universe, she is a savant with Asperger’s syndrome that allows her to do some amazing things."

"This season the characters will do things that viewers might not expect or agree with," said Chiappetta. "Agent Olivia Dunham (played by Anna Torv) will do something and the viewers will go ‘Oh My God, I don’t like the fact that she did that!’ but they’ll understand why she did this, there are reasons."

The writers have enjoyed the unique challenges of writing for two universes.

"Luckily, there is no shortage of new science that continues to inspire us," said Chiappetta. "There are even old ideas that we’d like to crack open and explore this season.”

"Thinking in another dimension is definitely a challenge, but the goal is to further these relationships and to take the show to a new level, it’s really two shows in one," said Whitman. "It's intriguing and scary. In each decision, you can become a different person -- what do you do and what does that choice do to you?"

On September 23, the third season of "Fringe" begins with Olivia Dunham, Walter Bishop and Peter Bishop (Joshua Jackson) digging a little deeper to untangle two universes with some subtle but consequential differences, while taking audiences on a thrilling and sometimes chilling ride.

Tuesday, September 21, 2010

Last week, surrounded by a cadre of big name CEOs, scientists, astronauts and educators, President Obama announced a major addition to the STEM program Educate to Innovate. The new initiative is a non-profit organization called Change the Equation, and is composed of hundreds of CEOs from large corporations dependent on science and math students, as well as science museums, libraries and even Nature Publishing - the group that owns Scientific American and the journal Nature.

In a public-private partnership backed by millions in donations from corporate America, the non-profit will focus specifically on improving science and technology teachers and inspiring kids to pursue degrees in the sciences.In his speech on Thursday, President Obama said that while profits might come from innovations at research labs and workshops, they don't start there. "It starts when a child learns that every star in the night sky is another sun," Obama said, "when a young girl swells with accomplishment after solving a tough math problem, when a young boy builds a model rocket and watches it soar, when an eager student peers through a microscope and discovers a whole new world. It's in these moments that we see why a quality education in science and math matters."

Highlighting the obvious - that America's science education trails the developed world significantly (and was recently ranked 21st in science and 25th in math) - the president said "America doesn't play for second place, and it certainly doesn't play for 25th."

Among the specifics mentioned, the following initiatives were put out in the press release accompanying the announcement. For a full description of the programs, see the WH press release.

* A "Youth Inspired Challenge" from the Association of Science-Technology Centers and local corporate and foundation support, it's being backed by 2 million promised hours of science enrichment to 25,000 students in 50 states.

* "Transforming Libraries and Museums into 21st Century Learning Labs" with $4 million from IMLS and the MacArthur Foundation, the effort will create 30 "YOUMedia centers" that are intended to be "hubs for youth engagement, creativity and hands-on learning," intended to inspire young people to create things rather than consume them.

* A "National STEM Video Game Challenge" put together by the Entertainment Software Association, Microsoft, AMD and several partners the effort will create a twice yearly competition for middle-school students creating and playing video games with 50k in prize money. The video games are to focus on STEM educational content.

* A "STEM Tool for State Policymakers" backed by $55 million from Raytheon, the tool will use the corporation's expertise and workers to help empower state level policymakers with ways to expand the STEM workforce in ways that utilize each states unique assets.

* An effort from the National Math Science Initiative designed to help military families excel in science and technology by expanding access to STEM AP classes in schools that serve a large number of military families. "NMSI’s support program for AP classes will make it possible to offer college-level courses for children in military families that will travel with them if they are transferred because the AP curriculum is consistently uniform regardless of the district they may attend."

* "Bridge to Science" from Nature Publishing will focus on building connections between parents, students and scientists. It will do this by "providing parents with easy-to-do experiments and creating an online platform for parents and children to become 'citizen scientists'. In addition, Nature and its affiliated journals will provide cost-free professional development for biology teachers interested in incorporating cutting-edge science, and recruit 1000 scientist-readers to participate in classrooms through efforts such as National Lab Day."

* An effort to bring the "passions of scientists and engineers into classrooms" with massive volunteering from HP employees nationwide to improve STEM education. In addition, the company will recruit retired scientists and engineers, and then match donations for volunteer hours. It will also collaborate with www.donorschoose.org and National Lab Day

* A "Scientists in the Classroom" campaign that aims to train and then deploy company scientists to work with teachers and students in classroom labs. The effort is backed by eight biotech companies and $4 million to date. "In partnership with efforts such as Citizen Schools and National Lab Day, the program will be launched in communities this fall in 10 states, reaching a run-rate of 1000 life scientists assisting in schools over five years."

* Additionally, ExxonMobil has committed to give $120 million to STEM education over the next three years, focusing on already successful programs such as UTeach. Merck is giving $19.5 million and partnering with Newark Public Schools, which are near the company's facilities, "to co-design an intensive professional development program for both teachers and administrators, expanding every year with the goal of district-wide adoption."

Monday, September 20, 2010

"A nightmare, long engendered in the modern mind by the mythology that follows in the wake of science, was falling off him. He had read of 'Space': at the back of his thinking for years had lurked the dismal fancy of the black, cold vacuity, the utter deadness, which was supposed to separate the worlds. He had not known how much it affected him till now..."

Like Lewis, many initially envision the vacuum of space as a place of "utter deadness" and it fuels cold thoughts of a universe devoid of action. But for decades, physicists attempting to unify quantum mechanics and relativity have been accidentally painting a contradictory and compelling picture of what actually separates the worlds. The subtle, yet critical properties of the vacuum are now needed to fully describe many bizarre phenomena in the cosmos.From the Dirac sea model of a vacuum as an ocean of negatively charged particles to the Casimir effect that dictates there will be a force between two or more objects because their presence alters the vacuum energy; such examples shatter the depressing misconception of an aether of nothingness.

Now, another possible example of the vacuum's importance has been added. In an upcoming issue of the journal Physical Review Letters (read the preprint on the arXiv), a group of physicists from Brazil show that the nature of a vacuum around a relativistic star -a rotating neutron star that requires general relativity to explain its behavior- could determine its fate.

A vacuum field gravitates due to its quantum properties and relativity implies that as such it can affect, and be affected by, the properties of spacetime. This is also the basis of Hawking Radiation, which dictates that a black hole should thermally radiate particles and lose mass. While the Brazilian authors say the Hawking effect is "virtually unobservable" in astrophysics, other so called semiclassical gravitation effects caused by the vacuum - such as the effects they describe on neutron stars - might be.

The theory goes like this: when a neutron star forms, it could disturb the vacuum in such a way that it causes its energy density to grow exponentially. In circumstances where the energy density becomes large enough, it would "take control over the evolution of the background spacetime," and could even become the dominant factor in deciding the outcome of how a star dies.

The group calls the process "awakening the vacuum" and when triggered, they say the effects could be seen in anywhere from the tiniest fraction of a second to a few billion years. If proven, the results could provide an important physical test of field theories, because a stable neutron star could confirm or deny what type of field surrounds it.

"Considering that 95-percent of the energy content of the universe is unknown, finding ways of testing the existence of free fields is very welcome," the authors state in the paper. "The awakening of the vacuum energy of certain fields may determine the ultimate fate of some relativistic stars."

Friday, September 17, 2010

iPhone apps seem like they can do anything these days. Need to answer an email? No problem! Want to see when the next bus is? Piece of cake! Want to toss virtual cows for fun? I don't know why you'd want to, but sure thing, coming right up!

Want to remote pilot a Micro Aerial Vehicle?

Yes, there IS an app for that!

PhysicsBuzz visited the lab of Dr. Missy Cummings, Director of the Humans and Automation Lab at MIT and former Navy fighter pilot who has been researching how to make complex automated systems people friendly (Extra points if you noticed the acronym for the lab is HAL).

Machines are capable of great things, but really are only as good as their operators.

That's where Dr. Cummings and her iPhones come in.

Her research focuses on looking at ways humans control machines and how to design control systems that people can intuitively "get." Because people interact with machines on a daily basis in countless ways, this research encompasses a lot of ground. One of her many projects is a tiny, four-rotor helicopter about the size of a small pizza box - a MAV - that can be flown using an iPhone. Small flying vehicles like that can be devilishly hard to control, needing constant attention to correct for changing wind conditions and the like. Buy a kit toy helicopter and the clerk will tell you that you are pretty much guaranteed to crash it sooner rather than later.

Using computers, the quad-copter automatically corrects for any imbalance it detects, and can hover above the ground without any person maintaining it. This simplifies the controls to the point that one needs only to mark out a point on a map for it to fly to and it can get there by itself.

After it reaches the general area, the iPhone switches to the "nudge controls" which lets a person control the flight in real time as if they were playing a videogame on their phone. Paul Quimby of the research lab explains:

To show off how easy it is to control, the team put together an interactive demonstration. They give a person who's never used the system before some basic instruction on how to tilt the iPhone to steer and then put them in charge of flying the little copter with a camera mounted on it. The copter is in a separate room that the person has never seen before, and is told to find and read an eye chart hidden somewhere within it. Though having received only minimal instruction, nine out of 14 participants were able to identify the smallest line of letters with 100-percent accuracy.

The idea is to show that computers have progressed to the point that vehicles can essentially fly themselves. Cummings and her team of tinkerers are working to further improve their robo-flyer. The team has on hand a couple of small LIDAR units, radar using lasers, and plan on hooking them to the bottom of the copter. This way the LIDAR will be able to map out the terrain as it flies to prevent itself from crashing if someone accidentally tells it to fly into a wall.

There are wide ranging commercial applications for an easy to use vehicle like this. Already law enforcement is looking into flying robots for surveillance, emergency services are keen on it for search and rescue and scientists are looking forward to its exploration capabilities. Just recently it was announced that a small ground robot will be used to explore the hidden passages in the Great Pyramid at Giza. Imagine the possibilities of a MAV flying between the walls of narrow caves or over the treetops of impassible jungles. Making technology simple to use blows open the door of possibilities. Plus it looks like tons of fun!

Thursday, September 16, 2010

NASA practices for a visit to the planet Mars and other destinations in the deserts of the Southwest.

What's it like to be on an alien planet? According to NASA, it could be pretty similar to a trip to the Grand Canyon.For many first time visitors to the southwestern United States, the high deserts between the magnificent Grand Canyon and the spires of Monument Valley in northern Arizona seem like an alien world -- and NASA feels the same way.

For the last two weeks, NASA's Desert Research and Technology Studies team -- or Desert RATS -- have tested rovers and equipment in the Arizona high country to prepare for the day when astronauts set foot on Mars and beyond.

If space travelers wanted to pick the best landing spot to explore and study the Earth, they would very likely consider northern Arizona, said David Portree of the United States Geological Survey in Flagstaff, Ariz. "There are so many geologic processes at work here in one relatively small area."

The Desert RATS have visited the area for two weeks every year since 1998, but this year the scientists are using two crews and two manned rovers for the first time in an effort to understand how best to communicate with both mission control and a scientific base camp. NASA wants to know if the crew would be more effective explorers if they were in constant contact with mission control or if instead they only had to call in a couple times a day. Many previous teams have studied the same areas, so NASA can rate the success of this year's team against other simulated missions.

"These space exploration vehicle concepts will help future astronauts explore various planetary surfaces ranging from near-Earth asteroids, the moon and/or Mars; build a long-term space presence; and conduct a wealth of science experiments," said James Rice of the NASA Goddard Space Flight Space Center in Greenbelt, Md., in a press release.

The mission hardware being tested consists of a variety of high-tech rovers and robots to help the astronauts perform experiments and move cargo. And because the living habitats and rovers are large and pressurized; unlike the Apollo astronauts, the Desert RATS don't have to wear space suits indoors, letting them live comfortably for their week-long stays in the rovers.

"All in all, we don’t have a large amount of space, but in general it is a comfy environment with all the accommodations that we need," said NASA Goddard geologist Jake Bleacher. "I've certainly been in harsher living conditions while conducting field work for my own research."

This isn't the first time NASA astronauts have used the high deserts of Arizona as a training ground. In the run up to the moon missions, lunar rovers and space suits were tested in explosives-derived blast craters created outside of Flagstaff to simulate what the Apollo astronauts would experience. In 1967, the agency replicated 10 acres of the of Tranquility lunar surface know as the Sea of Tranquility, the site where the Apollo 11 astronauts would eventually land.

Portree said the Grand Canyon area has been such a great proving ground for astronauts because the region has experienced lava flows, an asteroid impact, and areas of extreme erosion.

"Training was not only for moon landings -- it was also designed to teach astronauts who would be working in Earth orbit about geology so that they could understand what they saw from space," Portree said. "It's a natural place for teaching astronauts (or students) about different kinds of geology."

Wednesday, September 15, 2010

Have you ever noticed how the last bits of cereal in the bowl always seem to cling to one another, making it easy to spoon up the remaining stragglers? Physicists have -- and they've given it a name: the "Cheerios effect".

But this effect isn't exclusive to breakfast cereals. It also reveals itself in the way particles move in the air, pollen floats on the surface of water and galaxies cluster throughout the universe."If you put Cheerios in a bowl, they aggregate," said Arshad Kudrolli of Clark University in Worcester, Mass, who wrote a paper on the effect for the journal Physical Review Letters. "Or if you look at foam floating on a beer, you get clumps. That's because of surface tension."

Molecules in a fluid have a mutual attraction for each other and the effect creates surface tension -- a naturally resistant force that repels back against anything that pushes on the surface. It's surface tension that allows some insects, such as water striders, to walk across the water's surface -- and also fuels party tricks like floating paperclips or thumb tacks.

Kudrolli and colleague Michael Berhanu, also a physicist at Clark University, wanted to explore this effect in order to better understand similar phenomena in the natural world. So instead of going to the grocery store, they placed floating glass spheres in a funnel-shaped container of water. By altering the amount of water in the container, they could cause the glass spheres to either concentrate or disperse, simulating the various stages of the Cheerios effect.

"Physicists are interested in the Cheerios effect for a range of reasons," said postdoctoral researcher Dominic Vella from the University of Cambridge in the U.K., who was not involved in this research. "There are many instances of such systems in nature, so the insights that we gain from this model laboratory system may aid our qualitative understanding of more complicated systems."

Floating objects change the shape of a liquid's surface. If the molecules in an object are attracted to water, they are considered hydrophilic, or water-loving. Water gathers around the sides of the floating object and there will be a small depression beneath it called a meniscus. If the molecules in an object do not bond well with water, physicists say they are hydrophobic, or water-resistant, and the effect will create a small protruding bump underneath them -- a meniscus curved in the opposite direction.

In the case of your breakfast cereal, the Cheerios can be considered milk-philic because the O's create a small depression in the milk's surface, forcing them to fall in towards each other. Liquids can form similar features along the edges of a container and make the milk in your cereal bowl curve very slightly upward against the wall. Because Cheerios float, they will move up the curved surface of the milk and cause the O's to clump against the edges of the bowl as well.

"The bowl is also milk-philic so the meniscus goes up near it," said Vella. "This means that there is both an attraction between individual Cheerios and between a single Cheerio and the wall of the bowl."

Kusrolli and Berhanu found that when you throw just a handful of Cheerios into a bowl of milk they aggregate into hexagonal groups, but when you have many particles dispersed over a larger area -- such as pollen floating across a lake -- the particles gather into condensed areas with large gaps of empty space between the groups. While the driving force is different, Berhanu said this same effect can also be seen in the cosmos. Large clusters of galaxies and stars cling closely to each other while leaving vast amounts of empty space between them.

"If you look at the distributions of stars and galaxies, it's not random," said Kudrolli. "There are regions that are less dense, and there are regions that are more dense."

Tuesday, September 14, 2010

They say fusion is 50 years away. There were those who also said it was 50 years away two decades ago.

Either way, this week marks a significant date in whatever history fusion energy might have. Digging has begun at the ITER (thermonuclear was a bad word, so there's no longer an acronym) site in the south of France for the facility's Tokamak building. A tokomak is a torus shaped magnetic confinement device which is necessary to withstand the temperatures associated with fusion that are so high, solid materials can't hold them. As such, the building represents the future core of ITER. The construction start comes after decades of research, bureaucracy, politics infused debates and massive cost increases. In fact, the estimated cost has already tripled. Yet, a contract agreement was reached in May of this year that paved the way for digging to finally begin - 25 years after efforts towards an international thermonuclear fusion reactor were first crafted.

Working is really picking up – the first excavation works for the complex Tokamak building on the ITER site have now started. This is a major step forward after the signature of contract... The start of the excavation works demonstrates that the F4E (aka Fusion for Energy) contribution of buildings is progressing full speed ahead and on schedule. In tandem, development of the tender design for all the other buildings that are part of F4E’s contribution to the ITER project is also being carried out.

While the ITER folks are showing optimism about the start of construction on the facility, even many physicists are skeptical of the reality of the thing.

"It's possible that it can be done from the scientific point of view, but I think the economics are going to be quite troublesome."The radiation damage inside the thermonuclear reactor — a machine that is also known as a "tokamak" — would be so huge it would require replacing the expensive surrounding first wall, which faces the high-temperature plasma, every few years, Driscoll said. Another problem is material for high-temperature-resistant superconducting wires to make magnets for the ITER, he said.

For more details of the construction check out ITER. Anatoly Medetsky of The Moscow times has a very in-depth recent piece about the issues facing the future of the technology and the ITER project as well.

Monday, September 13, 2010

For an amputee, the body may continue feeling a phantom limb for long after the original is gone. Every arm or leg movement can carry the imaginary weight of a lost appendage, regardless of the presence of a prosthetic.

Yesterday, researchers from two groups in California published discoveries in the journal Nature Materials that should be well received by those with prosthetics. The two teams have each separately made significant advances in the ability to mimic human skin. Appropriately, the materials are being called "electric skin."The thin, flexible pressure sensing surfaces both have similar aims, yet use quite distinct approaches. Zhenan Bao, an associate professor of chemistry at Stanford University, and her team used organic electronics – with an elastic polymer called polydimethylsiloxane (PDMS) – to make their electric skin 1,000 times more sensitive than human skin.

From Nature News:

"Bao took a piece of PDMS measuring six centimetres square with pyramid-shaped chunks cut out of it at regular intervals. When the PDMS is squashed, the pyramid-shaped holes that were previously filled with air become filled with PDMS, changing the device's capacitance, or its ability to hold an electric charge.

To make it easier to detect the changes in capacitance, Bao stuck the PDMS capacitor onto an organic transistor, which can read out the differences as a change in current. The team used a grid of transistors to track pressure changes at different points across the material. "

The faux-skin is so sensitive that Bao and her team tested it by putting insects on it; including a butterfly and an actual fly. While the current material isn't stretchy enough to be used as a replacement skin for animals, the team hopes to have a prototype that can be incorporated into prosthetics by the end of the year.

The second team was based across the San Francisco Bay at UC Berkeley and used nanowire semiconductors that create a sensitive and flexible skin which can be draped over a conductive rubber with implanted transistors. The device then senses touch when something compresses the rubber and changes its electrical resistance, using very little power in the process.

Also from Nature News:

"In the 7-centimetre-square grid, the criss-crossing nanowires act as transistors. Each transistor is like a pixel, and the pressure-induced current change at each individual position can be read out. And because it's made mainly of rubber, the device is bendy. "Because we're using very small inorganic semiconductors, the devices are very flexible," explains Javey. He has bent the sensor into a U-shape with each arm of the 'U' separated by a gap of just 5 millimetres and it still works."

Interestingly, the Berkeley team mentions their prosthetic skin not only has applications for biomedical devices, but also applies to the interactions of artificial intelligence and humans (Data's artificial skin in First Contact anyone?). They also mention that while such technology has been explored before, it has yet to be created in a cost-effective and sufficiently sensitive way.

Friday, September 10, 2010

An american named Tom Lowe has nabbed the Royal Observatory's prize for astronomy photographer of the year with this stunning image of an ancient Bristlecone pine with the cosmos as a back drop. The contest was broken into three categories for individual images and a prize was given for Earth and Space (which Lowe also won), Deep Space and Our Solar System. Another prize was also awarded for young astronomy photographer of the year.

Image description from the contest website:

The gnarled branches of an ancient tree align with a view of our Milky Way galaxy. The Milky Way is a flat, disc-like structure of stars, gas and dust measuring more than 100,000 light years across. Our Sun lies within the disc, about two-thirds of the way out from the centre, so we see the Milky Way as a bright band encircling the sky. This view is looking towards the centre of our galaxy, 26,000 light years away, where dark clouds of dust blot out the light of more distant stars. What appears to be an artiﬁcial satellite orbiting the Earth makes a faint streak of light across the centre of the image.

Also, as part of the competition this year, the Royal Observatory has introduced a neat new way of tapping into the popular photo site Flickr to create a map of the night sky. The observatory is asking the public to upload its photos to their album and use "astrotags" to cite the date, time and object. They then use a bot to finish off the astrotag and add things like RA and dec to create the final map.
Read the rest of the post . . .

Thursday, September 09, 2010

It can happen when massive galaxies collide, or it can be predetermined by the conditions the galaxies formed under. But new observations published by the journal Astronomy and Astrophysics show that black holes at the centers of galaxies can strip precious star forming material from the surrounding area and hurl it out into the blackness of space, eventually robbing the galaxy of what it needs to produce new stars.From the paper:

"The depletion of gas resulting from quasar driven outflows should eventually stop star formation across the host galaxy and lead to 'suicide' by starvation."

In the research, which was released last month, astronomers from France and Italy used the Plateau de Bure Interferometer in the French Alps to observe a distant galactic center expel as much as 700 solar masses of material from the galaxy per year.

It recent years, observations have shown that supermassive black holes exist at the center of many galaxies and even play a part in galactic evolution. And while it's widely known that black holes suck in stars that venture too close, they also heat up the surrounding gas and dust required for star formation. As they do, the formerly cold gas around these cosmic vacuum cleaners begins to glow.

Finally, once the supermassive black hole has reached a mass millions of times larger than the sun, it heats the gas enough that it actually spews from the solar system in great winds that slowly rob the galaxy of future worlds and future black hole food. The group estimates if the galaxy loses 700 solar masses of this molecular gas every year, within 140 million years star formation wouldn't be possible and they observe that the central regions closer to the black hole are already devoid of young stars.

According to the astronomers, the observations also help solve two cosmic mysteries; why there are so many fewer large galaxies than what computer models would predict, and why so many galaxies are colored red - an indication of old star populations.

Wednesday, September 08, 2010

WASHINGTON (ISNS) -- Tractor beams, energy rays that can move objects, are a science fiction mainstay. But now they are becoming a reality -- at least for moving very tiny objects.

Researchers from the Australian National University have announced that they have built a device that can move small particles a meter and a half using only the power of light.

Physicists have been able to manipulate tiny particles over miniscule distances by using lasers for years. Optical tweezers that can move particles a few millimeters are common.Andrei Rode, a researcher involved with the project, said that existing optical tweezers are able to move particles the size of a bacterium a few millimeters in a liquid. Their new technique can move objects one hundred times that size over a distance of a meter or more.

The device works by shining a hollow laser beam around tiny glass particles. The air surrounding the particle heats up, while the dark center of the beam stays cool. When the particle starts to drift out of the middle and into the bright laser beam, the force of heated air molecules bouncing around and hitting the particle's surface is enough to nudge it back to the center.

A small amount of light also seeps into the darker middle part of the beam, heating the air on one side of the particle and pushing it along the length of the laser beam. If another such laser is lined up on the opposite side of the beam, the speed and direction the particle moves can be easily manipulated by changing the brightness of the beams.

Rode said that their technique could likely work over even longer distances than they tested.

"With the particles and the laser we use, I would guess up to 10 meters in air should not be a problem. The max distance we had was 1.5 meters, which was limited by the size of the optical table in the lab," Rode said.

Because this technique needs heated gas to push the particles around, it can't work in the vacuum of outer space like the tractor beams in Star Trek. But on Earth there are many possible applications for the technology. The meter-long distances that the research team was able to move the particles could open up new avenues for laser tweezers in the transport of dangerous substances and microbes, and for sample taking and biomedical research.

"There is the possibility that one could use the hollow spheres as a means of chemical delivery agents, or microscopic containers of some kind, but some more work would need to be done here just to check what happens inside the spheres, in terms of sample heating," said David McGloin, a physicist at the University of Dundee in the U.K not connected with the Australian team.

Tuesday, September 07, 2010

You should absolutely, under no circumstances, attempt to recreate the following; but if you were to, here's what you would need and what it would look like.

In the last two weeks, both water and fire tornadoes have been widely covered by the media. First there was the dramatic shots from Japan of a so-called "waterspout," then there was the unbelievable footage of this fire tornado in Brazil, followed immediately by this one from Hawaii. And as any good physicists would have, we immediately thought 'I want to do that!'

Of course, APS requires me to tell you not to try this at home. So, here's how you would do this, if you were to find yourself attempting to do it, which you should absolutely under no circumstances try to do.

First, you should not acquire a bottle of lighter fluid, Play-Doh, a fire extinguisher, a few small pieces of sponge, a metal cup, a lazy Susan and a large metal screen. But if you did have all of those in the same place, certainly do not soak the sponges in a small amount of water and lighter fluid and then place them securely in the center of the lazy Susan. By no means would you then want to light them on fire and keep a metal pan of some sort close by to eventually cut off the oxygen and put it out. And, if you happened to have gotten so far, you would definitely not want to put a wire screen around the burning sponges and hold it down with Play-Doh before spinning it.

However, if you did all of that you would have your own fire tornado. Which you can see from this video is clearly not at all awesome or worth recreating.
Read the rest of the post . . .

Friday, September 03, 2010

Rare isotopes preserved in fossil teeth could serve as an ancient thermometer.

Tyrannosaurus rex is often portrayed as a cold-blooded killer, but whether the Cretaceous-era dinosaur actually had a slow, reptilian-like metabolism or a faster, more bird-like metabolism is still a mystery.

Now a new technique using rare isotopes preserved in tooth enamel is proving to be a reliable way of determining body temperatures of recently extinct animals like woolly mammoths and researchers are hoping the method will work on even older fossils, including dinosaurs.A team of researchers led by Robert Eagle, a biologist at the California Institute of Technology in Pasadena, California, found that rare, heavy isotopes of carbon-13 and oxygen-18 clump together differently depending on temperature.

"It's basic thermodynamics: At warmer temperatures, you get a more random distribution of these isotopes with less clumping," Eagle said. "As temperature decreases things slow down and you begin to see more bonding."

When this bonding takes place within an organism, such as in the formation of the mineral apatite to form tooth enamel, the pattern of bonds preserves a record of the animal's body temperature, within a few degrees.

To test the new technique, Eagle and colleagues began by experimenting with teeth from modern animals like the white rhinoceros, Indian elephant, Nile crocodile and sand tiger shark. The temperatures produced using the isotope technique matched the known body temperatures for all four species within 1 degree Celsius.

The team then turned their attention to 20,000 year old woolly mammoth teeth and 12 million year old alligator and rhino teeth with similar success, as they reported in the Proceedings of the National Academy of Sciences in May.

Since this is the first method for directly measuring the body temperatures of extinct vertebrates, Eagle and colleagues compared the temperature data for mammoths, alligators and rhinos with their modern counterparts, which are thought to have very similar metabolisms to their ancient relatives.

"This study was really a proof of concept," Eagle said. "The really exciting applications are the ones that are around the corner, as we go even further back in time."

Based on other lines of evidence, such as growth rates, Kevin Padian, an evolutionary biologist at the University of California, Berkeley, who was not involved in the new study, said it's likely that some species of dinosaurs had a high metabolic rate and were able to control their own body temperatures, much like mammals and birds today.

"I think we already understand a lot about their metabolism, but we don't have a lot of hard evidence," Padian said. "This new study could provide an entirely new line of evidence, which is great."

But while determining relative body temperatures will certainly be helpful, evolutionary biologist Padian said that the findings won't completely solve the dinosaurs' metabolic mystery.

Whether dinosaurs were homeothermic and maintained one consistent body temperature like many species of mammals or were heterothermic and could adjust their body temperatures, like birds, cannot be answered by the isotopic technique, he said.

Eagle and colleagues plan to continue using their isotopic method to test progressively older fossils, including species of dinosaurs and early mammals.

"So far we've seen that tooth enamel is very hard material that is quite resistant to chemical change over long time scales," Eagle said.

If the technique proves successful on older fossils, Padian hopes it will be also be applied to a wide variety of dinosaurs and early mammals from different latitudes and at varying stages of evolutionary development.

"They could paint a very interesting picture using this technique," Padian said. "The more things you try the more insight you get. That's how science works."

Thursday, September 02, 2010

Yesterday an advisory panel at Fermilab doubled down on the center's Tevatron once again, giving the aging accelerator one last push to find the elusive Higgs Boson in the race with CERN. The panel is recommending that the instrument receive continued funding of $150-million, extending its operations through 2014. The Tevatron is currently scheduled to end operations after 2011.

The information came on the heels of protests at CERN last week over the half-billion dollar budget cut imposed on that facility by European governments. CERN researchers were quick to warn that such a massive cut back might further increase the risk of another breakdown similar to the one that forced the collider to close for 14-months.The Tevatron has been battling against obsolescence since the Large Hadron Collider first came online, but after the LHC's embarrassing breakdown and a rash of recent discoveries made on the Tevatron, Fermilab is showing they might be able to find the Higgs despite being seriously outgunned.

However, extending funding means other experiments that would have used the money will now take a back seat as the accelerator explores the remaining mass ranges where the Higgs might be hiding. The D0 and CDF - the Tevatron's two main instruments - have already ruled out most of the range that the mass carrying particle was thought to be in, however, an extra three years should give physicists enough time to rule out the remainder of the predicted range.

Wednesday, September 01, 2010

Michael Duff, a professor at the Imperial College in London, was at a conference in Tasmania watching a colleague give a talk on quantum entanglement when he realized the equations being presented looked rather similar to a set of equations he had created to describe string theory inside black holes. When he returned to London, he checked the formulas against each other and discovered that not only were they similar, but the equations were in fact the same.

It's now thought that Duff's discovery might allow physicists to predict the behavior of entangled quantum particles with string theory. They're calling it the "stringy black hole/qubit correspondence." If true, this could prove to be the method needed to take string theory from a "framework" to an experimentally testable theory, something its critics have chided it over for two decades.The research is set to be published tomorrow in the journal Physical Review Letters and does not itself confirm string theory (let alone show that it is the theory of everything), but because predictions can be made about entanglement, it does give hope that string theory might now find a home in the lab. Though, there is no explanation as to how the entanglement and string theory might be related.

From Physorg.com:

The discovery that string theory seems to make predictions about quantum entanglement is completely unexpected, but because quantum entanglement can be measured in the lab, it does mean that at last researchers can test predictions based on string theory. There is no obvious connection to explain why a theory that is being developed to describe the fundamental workings of our universe is useful for predicting the behaviour of entangled quantum systems. "This may be telling us something very deep about the world we live in, or it may be no more than a quirky coincidence", concluded Professor Duff. "Either way, it's useful."